PEEK Injection Moulding: High-Performance Polymer Molding
PEEK injection moulding: high-temperature, chemical-resistant engineering polymer. Tensile strength 100MPa, continuous use 250°C. Medical and aerospace grade.
PEEK Injection Moulding: High-Performance Polymer Molding
PEEK (Polyetheretherketone) is a top-tier engineering thermoplastic that sits at the apex of the performance pyramid. With a continuous use temperature of 250°C, tensile strength of 100 MPa, and near-universal chemical resistance, PEEK outperforms almost every other mouldable polymer in demanding environments.
At FIRMFG, we specialize in PEEK injection moulding with the specialized high-temperature equipment and processing expertise this premium material demands. From medical implants to aerospace engine components, we deliver PEEK parts that meet the most stringent quality and performance requirements.
This guide covers PEEK material properties, available grades, processing requirements, design guidelines, and comparisons with other high-performance polymers. Or, skip ahead and request a quote for an immediate price and lead time.
PEEK Quick Specifications
Key material and processing specifications for PEEK injection moulding.
| Specification | Value |
|---|---|
| Tensile Strength | 100 MPa |
| Continuous Use Temperature | 250°C |
| Density | 1.32 g/cm³ |
| Processing Temperature | 370 – 400°C |
| Mold Temperature | 180 – 200°C |
| Shrinkage (Unfilled) | 1.2% |
PEEK Material Properties
Comprehensive mechanical, thermal, chemical, and tribological properties across PEEK grades.
| Property | Unfilled PEEK | PEEK-GF30 | PEEK-CF30 |
|---|---|---|---|
| Tensile Strength | 100 MPa | 170 MPa | 220 MPa |
| Flexural Strength | 170 MPa | 260 MPa | 310 MPa |
| Compressive Strength | 120 MPa | 180 MPa | 210 MPa |
| Heat Deflection Temp (HDT) | 160°C | 315°C | 315°C |
| Continuous Use Temp | 250°C | 250°C | 250°C |
| CLTE (Coefficient) | 47 µm/m·°C | 22 µm/m·°C | 15 µm/m·°C |
| Chemical Resistance | Excellent | Excellent | Excellent |
| Flammability (UL94) | V-0 | V-0 | V-0 |
| Limiting Oxygen Index | 35% | 38% | 40% |
| Friction Coefficient | 0.35 | 0.40 | 0.25 |
| PV Limit | 0.2 MPa·m/s | 0.3 MPa·m/s | 0.5 MPa·m/s |
All values are typical nominal values from material datasheets. Actual properties vary with processing conditions, crystallinity, and part geometry. Reinforced grades show significant improvements in stiffness, strength, and thermal performance.
PEEK Grades Available
Five primary PEEK formulations to match your specific performance and application requirements.
Unfilled PEEK
General-purpose PEEK with balanced mechanical, thermal, and chemical properties. Natural color (beige) or black. The baseline grade for most engineering applications.
Best for: General engineering components, electrical insulation
PEEK-GF30
30% glass fiber reinforced PEEK. Significantly higher stiffness and dimensional stability while retaining chemical resistance. Reduced shrinkage and improved creep resistance.
Best for: Structural components requiring high rigidity
PEEK-CF30
30% carbon fiber reinforced PEEK. Highest strength-to-weight ratio of all PEEK grades. Excellent stiffness, low thermal expansion, and inherent lubricity from carbon fibers.
Best for: Aerospace structural parts, load-bearing components
PEEK-Bearing
PTFE and graphite modified PEEK. Superior wear resistance and low friction coefficient. Self-lubricating formulation with high PV limits for demanding tribological applications.
Best for: Bearings, bushings, wear rings, dynamic seals
Medical-Grade PEEK
Implantable-grade PEEK meeting ISO 10993 biocompatibility standards. USP Class VI compliant. Gamma and EtO sterilizable. Lot traceable with full documentation.
Best for: Spinal implants, orthopedic devices, dental abutments
Processing Requirements
PEEK demands specialized high-temperature equipment and precise process control. These requirements are non-negotiable for quality parts.
High-Temperature Barrel
Barrel temperatures of 370–400°C are required to achieve proper melt viscosity. Standard moulding machines typically max out at 350°C, so specialized high-temp machines with bimetallic barrels and corrosion-resistant screws are mandatory. PEEK melt is slightly corrosive, requiring hardened or bimetallic screw and barrel construction.
Mold Temperature
Mold temperature of 180–200°C is essential for proper crystallization. Insufficient mold temperature produces amorphous parts with inferior mechanical properties and dimensional instability. Oil-heated molds with high-capacity temperature controllers are required — standard water-heated systems cannot reach these temperatures.
Drying
PEEK must be dried at 150°C for 3–4 hours before processing. Even small amounts of moisture cause hydrolytic degradation, reducing molecular weight and mechanical properties. Desiccant dryers with high-temperature capability are required, and resin should be processed immediately after drying to prevent moisture reabsorption.
Crystallization & Cooling
Controlled cooling rate is critical for achieving optimal crystallinity (30–35%). Rapid cooling produces amorphous parts; slow, controlled cooling through the crystallization temperature range (300–150°C) ensures proper crystal structure. Annealing at 200–230°C can optimize crystallinity in finished parts for maximum performance.
Design for PEEK Moulding (DFM)
Design guidelines specific to PEEK material behavior and processing characteristics.
| Design Parameter | Recommended Value |
|---|---|
| Minimum Wall Thickness | 1.0 mm |
| Shrinkage (Unfilled) | 1.2% |
| Shrinkage (Reinforced) | 0.3 – 0.5% |
| Draft Angle | 1.5° |
| Tolerance (Precision) | ±0.05 mm |
| Crystallization Control | Mold temp 180–200°C required |
| Rib Design | 50% of nominal wall thickness |
| Flow Considerations | Runner and gate sizing for high viscosity |
Reinforced PEEK grades (GF30, CF30) exhibit lower shrinkage and warpage than unfilled PEEK, making them preferable for tight-tolerance and large flat parts. Anisotropic shrinkage in fiber-filled grades must be accounted for in mold design.
Post-Processing Options
PEEK supports a full range of post-moulding processes to achieve final part specifications.
Annealing
Controlled thermal treatment to optimize crystallinity and relieve internal stresses. Annealing at 200–230°C improves dimensional stability and mechanical performance for demanding applications.
CNC Finishing
Precision CNC machining for tight-tolerance features, threads, and mating surfaces. PEEK machines well with carbide tooling, enabling ±0.02mm precision on critical dimensions.
Laser Marking
Permanent laser marking for part identification, traceability, and branding. Compatible with medical-grade PEEK for UDI compliance without compromising surface integrity.
Sterilization
EtO sterilization, gamma irradiation, and autoclave (134°C) compatible. Medical-grade PEEK maintains mechanical properties after repeated sterilization cycles for reusable devices.
Need precision CNC finishing on PEEK parts? Visit our CNC Machining PEEK page for capabilities and tolerances.
PEEK vs PPS vs PAI Comparison
How PEEK compares to other high-performance engineering polymers.
| Feature | PEEK | PPS | PAI |
|---|---|---|---|
| Max Service Temp | 250°C | 200°C | 260°C |
| Tensile Strength | 100 MPa | 85 MPa | 95 MPa |
| Chemical Resistance | Excellent | Excellent | Good |
| Wear Resistance | Very Good | Good | Excellent |
| Cost (Relative) | $$$$ | $$ | $$$$ |
| Processing Difficulty | High | Medium | Very High |
| Primary Applications | Medical, aerospace, semiconductor | Electrical, automotive, chemical | Aerospace, defense, oil & gas |
PEEK offers the best overall balance of temperature resistance, mechanical properties, and processability. PPS is more economical for moderate-temperature chemical applications, while PAI exceeds PEEK in wear and temperature but at significantly higher cost and processing difficulty.
PEEK Injection Moulding FAQ
Answers to the most common questions about PEEK injection moulding at FIRMFG.
QWhat is the maximum operating temperature for PEEK?
PEEK has a continuous service temperature of 250°C. The glass transition temperature (Tg) is 143°C and the melting point is 343°C. Glass fiber reinforced grades (PEEK-GF30) achieve a heat deflection temperature of 315°C. PEEK retains over 50% of its flexural modulus at 200°C, making it one of the few thermoplastics suitable for sustained high-temperature service without significant loss of mechanical properties.
QIs PEEK suitable for medical implants?
Yes. Medical-grade PEEK (also called PEEK-OPTIMA) meets ISO 10993 biocompatibility standards and is USP Class VI compliant. It is widely used for spinal fusion cages, orthopedic devices, cranial implants, and dental abutments. PEEK is radiolucent (transparent to X-rays), has a modulus similar to cortical bone (reducing stress shielding), and is MRI-compatible. FIRMFG supplies implantable-grade PEEK with full lot traceability and material certificates.
QHow chemically resistant is PEEK?
PEEK exhibits exceptional chemical resistance across a wide range of substances. It resists almost all organic and inorganic solvents, acids, bases, and salt solutions at temperatures up to 200°C. PEEK is attacked only by concentrated sulfuric acid, concentrated nitric acid, and some halogenated solvents under extreme conditions. This chemical inertness makes PEEK ideal for pump components, valve seats, and seals in aggressive chemical environments where most other plastics fail rapidly.
QWhat temperature is required to injection mould PEEK?
PEEK requires a barrel temperature of 370–400°C and a mold temperature of 180–200°C. These temperatures are significantly higher than standard engineering plastics like nylon (220–280°C). The processing equipment must use corrosion-resistant screws and barrels (bimetallic or fully hardened) to withstand the high temperatures and PEEK's slightly corrosive melt. Proper drying at 150°C for 3–4 hours is essential, as moisture causes hydrolytic degradation during processing.
QHow much does PEEK injection moulding cost?
PEEK is a premium engineering polymer, costing approximately $80–$150 per kg for unfilled grades, $120–$200 for glass-filled, and $150–$250 for carbon-filled. Material cost dominates the per-part price for smaller components. A 10g part in unfilled PEEK might cost $1.50 in material alone, versus $0.10 for nylon. However, PEEK's exceptional performance often eliminates the need for metal components, reducing overall assembly weight and cost. Mold costs are comparable to other engineering plastics ($3,000–$15,000 depending on complexity).
QCan PEEK parts be machined after moulding?
Yes. PEEK machines excellently with carbide or diamond tooling, achieving tolerances of ±0.02mm. Post-moulding CNC machining is common for tight-tolerance features, threaded holes, and mating surfaces that cannot be moulded directly. Annealing before machining is recommended to relieve internal stresses and prevent warpage. FIRMFG offers combined moulding and CNC finishing services for PEEK components requiring both complex geometries and precision tolerances. Learn more at our CNC machining PEEK service.
Applications of PEEK Injection Moulding
PEEK serves industries where standard plastics cannot survive the operating environment.
Medical Implants
Spinal cages, orthopedic devices, dental abutments
Aerospace Engine Parts
Engine components, structural brackets, insulation
Semiconductor Components
Wafer handling, chamber parts, IC test sockets
High-Temp Seals
Dynamic seals, valve seats, pump components
Chemical Parts
Pump impellers, valve bodies, pipe linings
Automotive Under-Hood
Sensors, connectors, thermal shields
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Upload your CAD files and get a free PEEK injection moulding quote within 24 hours. Specialized high-temperature processing, medical and aerospace grades available. Full traceability and material certification.